The present invention relates to a vehicular headlamp having an inclination detector for detecting whether or not the irradiation angle of the headlamp in a horizontal plane is correct, and more particularly to a headlamp which is designed so that, when the irradiation angle is not correct, it can be adjusted with ease to a correct value.
One example of a vehicular headlamp aiming mechanism is disclosed, for instance, in commonly assigned U.S. patent application Ser. No. 07/370,949. A conventional aiming mechanism of this type will be described with reference to a movable reflector type headlamp.
As shown in FIG. 11, a reflector 2 is supported on a lamp body 1 at three points, i.e., one swing fulcrum 3 fixed to the lamp body, and two aiming points 4 and 5 which are engaged with two aiming screws 4a and 5a coupled to the lamp body so that their distances from the lamp body can be adjusted as desired. More specifically, the one swing fulcrum 3 and the two aiming points 4 and 5 are positioned in such a manner that the horizontal axis Lx connecting the horizontal aiming point 4 and the swing fulcrum 3 and the vertical axis Ly connecting the vertical aiming point 5 and the swing fulcrum 3 are perpendicular to each other as viewed from the front. By turning the aiming screws 4a and 5a, the distances of the aiming points 4 and 5 from the lamp body are changed so that the reflector 2 is swung about the horizontal axis Lx and the vertical axis Ly, that is, the axis of irradiation of the headlamp is swung both in a horizontal plane and in a vertical plane.
Between the lamp body 1 and the reflector 2 is provided an inclination detector 6 which is composed of a movable holder which can be moved back and forth, and a slider which is coupled to the movable holder in such a manner that the slider is movable back and forth together with the reflector 2. The slider is graduated, and the movable holder has a reference point marked on it. The inclination detector 6 thus provided indicates from the position of the reference point the amount of inclination of the reflector 2 in a horizontal plane.
However, the headlamp with the above type of inclination detector is disadvantaqeous in that the movable holder protrudes from the rear side of the lamp body. Therefore, in operating the movable holder to set its reference point to the scale reading "0" (hereinafter referred to as "a zero point adjustment" when applicable), it is necessary for the operator to bend over the lamp and to stretch his hand towards the rear wall of the lamp body. Thus, the zero point adjustment is considerably troublesome for the operator.